.TH relup 5 "sasl 4.2.1" "Ericsson AB" "Files"
.SH NAME
relup \- Release upgrade file
.SH DESCRIPTION
.LP
The \fIrelease upgrade file\fR\& describes how a release is upgraded in a running system\&.
.LP
This file is automatically generated by \fIsystools:make_relup/3,4\fR\&, using a release resource file (\fI\&.rel\fR\&), application resource files (\fI\&.app\fR\&), and application upgrade files (\fI\&.appup\fR\&) as input\&.
.SH "FILE SYNTAX"

.LP
In a target system, the release upgrade file is to be located in directory \fI$ROOT/releases/Vsn\fR\&\&.
.LP
The \fIrelup\fR\& file contains one single Erlang term, which defines the instructions used to upgrade the release\&. The file has the following syntax:
.LP
.nf

{Vsn,
  [{UpFromVsn, Descr, Instructions}, ...],
  [{DownToVsn, Descr, Instructions}, ...]}.
.fi
.RS 2
.TP 2
.B
\fIVsn = string()\fR\&:
Current release version\&.
.TP 2
.B
\fIUpFromVsn = string()\fR\&:
Earlier version of the release to upgrade from\&.
.TP 2
.B
\fIDescr = term()\fR\&:
A user-defined parameter passed from the function \fIsystools:make_relup/3,4\fR\&\&. It is used in the return value of \fIrelease_handler:install_release/1,2\fR\&\&.
.TP 2
.B
\fIInstructions\fR\&:
A list of low-level release upgrade instructions, see \fIappup(5)\fR\&\&. It consists of the release upgrade instructions from the respective application upgrade files (high-level instructions are translated to low-level instructions), in the same order as in the start script\&.
.TP 2
.B
\fIDownToVsn = string()\fR\&:
Earlier version of the release to downgrade to\&.
.RE
.SH "SEE ALSO"

.LP
\fIapp(5)\fR\&, \fIappup(5)\fR\&, \fIrel(5)\fR\&, \fIrelease_handler(3erl)\fR\&, \fIsystools(3erl)\fR\&